Solutions for Mesh Hair alpha + lighting?

[Kouki Elska]

Hello all. I had a concern about creating mesh hair... I've actually been making hair for a long time in SL (since 2007), but the hair I've made before was either with sculpties or mesh but in anime/toon style with no alpha (Think of Sims 4 hair). So I've never before really had to deal much with alpha-textured hair... but now that I'm trying to get into making mesh hair with realistic alpha that can work for the realistic mesh faces to give the soft/wispy hair look... I'm having issues and would like some advice from anyone who makes hair or otherwise deals with alpha bugs on mesh.

I have attached two photos at the bottom, one where the problem is clearly visible, and the other where the problem does not exist... and the problem has to do with the lighting in-world.

There is a glitch that if you use the advanced lighting model and stand near certain kinds of lighting like spot lighting, the alpha ends of the hair will mismatch the rest of the hair by being more dimly-lit than the non-alpha or alpha-masked parts of the hair… The difference becomes more and more pronouonced as the "Ambiance" of the lighting goes up (this photo shows it under a spotlight with Ambiance of 1.0).

The only fix I could find was to either not stand near spot lights… disable local lights/advanced lighting model temporarily… or make a copy of the hair and using “edit linked objects” or “select texture”, select the alpha part of the hair, and switch the texture’s alpha mode to “Alpha Mask” with a “Mask cutoff” of 125.

But, I am trying to figure out if there's a way around this, because it's honestly kind of unreasonable to expect customers to just avoid areas and not complain or feel ripped-off (even though the hair is a group gift, but I want to learn for future hair I will want to make/sell, and update a fix for this one). And while setting the alpha mode to "Alpha Mask" does solve it, it makes the hair look too sharp like it's wet, which I am trying to avoid. >.< And while other hairs I have worn by other creators which has plenty of alpha (such as Dura or really any hair store!) also have some degree of glitching in spotlights, it's not as bad or obvious as with my hair. Unfortunately, I don't have hair creator friends to ask for advice, so I'm posting here.

 

If there's any tips for how you make hair with alpha, that manages to:

A: not suffer from the alpha bug where the strands bleed through each other, and...

B: not suffer so obviously from the spot lighting in SL.

 

I'd be very grateful.

 

Thanks in advance.

---

 

Inside a regular home in region windlight:

Inside the same home with flatter windlight, and facing away from the spot light source:

Edited January 18, 2018 by Kouki Elska

[Kouki Elska]

Alright, it seems I've found at least one possible solution while experimenting in Blender, though it's not perfect.

I explain it here: http://audaxinc.net/post/169866082344/alright-i-think-i-have-found-somewhat-of-a
 

And this is the comparison picture:

Edited January 19, 2018 by Kouki Elska

[KennyChidorie]

Solutions:

Before, i want show to you next resolution:

Helping tools - Recalculate and Smooth. Second -> work with Alpha mask and Blending mask both.

[Kyrah Abattoir]

The "fix" is opening a Jira about it and asking Linden Lab to fix their shader, cause this is not normal.

[Kweopi]

they will. and if they focus on that will be fixed in 4-5 years

[Penny Patton]

It's not as abnormal as you think. Videogames avoid using blended alpha because of this and other reasons (such as alpha sorting issues). Your best bet is to make hair textures that look good as masked alpha.

[ChinRey]

On 1/19/2018 at 1:10 AM, Kouki Elska said:

I explain it here: http://audaxinc.net/post/169866082344/alright-i-think-i-have-found-somewhat-of-a

So you combine alpha masking and blending? That's a really clever trick that can be useful for other items too and as far as I know, it's a brand new one. Great work! 

 

On 1/18/2018 at 2:30 AM, Kouki Elska said:

If there's any tips for how you make hair with alpha, that manages to:

A: not suffer from the alpha bug where the strands bleed through each other, and...

When you're dealing with the alpha sorting bug it's important to keep in mind that the viewer sorts the alpha surfaces according to the distances not from the srufaces but from the center of each object. You can reduce the problem significantly by splitting the mesh into several linekd one, each with its own carefully chosen center.

[Cackle Amore]

Ya sadly glitchy transparency has been something that's plagued video games for quite some time. That's why you're more likely to see things use mask instead.